Conventionally, a high frequency heating apparatus with a range hood has an automatic cover that opens or closes automatically, and a gas flow changing mechanism for allowing a user to change a gas exhaust direction from a blower to circulate byproduct gas, which is generated from a heating cooker installed below an apparatus main body and suctioned into the range hood through the lower portion of the apparatus main body, in an indoor space via an exhaust opening provided in an upper front portion of the apparatus main body or to exhaust it outside through a top portion or a rear portion of the apparatus main body (see, for example, U.S. Pat. No. 5,981,929).
In the apparatus with the above configuration, the automatic cover for closing the exhaust opening provided in the upper front portion of the apparatus main body is opened to provide a passageway for an exhaust air or a suction air for cooling electric components of the apparatus when the high frequency heating apparatus (for example, a microwave oven) is in an heating operation. Besides, the cover is also opened when the blower is operating regardless of an exhaust direction of the blower.
In the conventional apparatus, however, the automatic cover is opened even when its open state is not necessary, for example, when the gas exhaust direction of the blower is set for outdoor ventilation. Furthermore, the automatic cover is also opened to provide an opening for intake or exhaustion of air for cooling the electric components of the microwave oven when the microwave oven is in a heating operation. Accordingly, since the cover is opened too frequently even when it need not be opened, the advantage of installing the automatic cover to improve the aesthetic feature of the microwave oven by reducing the opening area on the surface of the apparatus main body cannot be fully utilized.